There are many materials that have ferroelectric properties, which are indicated by the ability of a material to achieve and maintain a high degree of polarization (e.g., alignment of the atomic or molecular dipoles that comprise the material) even in the absence of an external electric field. In some materials, groups of dipoles can be similarly aligned in regions known as “domains” within the material. When a significant number of the domains of a material are aligned in the same direction, the material becomes highly polarized and can maintain a specific orientation, which can be useful for many applications.
For example, highly polarized material can be used in computer memory cells. In such an application, it is important to have a highly polarized material to prevent stray electrical voltages from reversing a value written to a memory cell by the computer system. Various methods have been used to improve the disturb resistance (e.g., ability to resist inadvertent value reversal) of the material used within the memory cell.
For example, one conventional method includes formation of the memory cell material (e.g., a polymer) on a substrate followed by formation of an electrode on top of the memory cell material. The memory cell material is then heated so that the dipoles within the domains of the material can overcome the steric hindrances and internal electrostatic forces of the material (e.g., are free to be re-aligned). During the heating process (e.g., annealing), the electrode formed on top of the memory cell material can be used to apply an electric field to the memory cell material to align the dipoles, and hence, the domains, of the memory cell material in a common direction. However, use of the electrode to apply the electric field typically results in degradation of the interface between the electrode and the memory cell material. It is believed that the degradation of the interface results from a reaction between the memory cell material and the metal of the electrode.